Soft tissue-implant interface is an important anatomical feature contributing to the long-term success of dental implants. Based on the available evidence, different factors may influence biological width around implants including the surgical technique, implant loading, implant surface properties, abutment materials, implant position, and width of the peri-implant mucosa. The purpose of the present review was critical evaluation of the available data, regarding the factors that may influence the biologic width around implants and their subsequent effect on clinical performance of implants. Available literature on this subject published primarily in English from 1921 to 2014, was found by searching several electronic databases and by hand searching relevant journals as well. Totally, 70 relevant articles were selected for this narrative review. The structure of peri-implant mucosa has many similarities, as well as differences with its periodontal counterpart. Most studies report larger values for peri-implant biologic width compared to that of natural teeth. This literature review yielded contradictory data regarding the dimensions of the biologic width when different influential factors were taken into account. .